diff --git a/src/core/config/secure_transport.h b/src/core/config/secure_transport.h
index 854700d91..eb636baa7 100644
--- a/src/core/config/secure_transport.h
+++ b/src/core/config/secure_transport.h
@@ -72,7 +72,7 @@
      OPENTHREAD_CONFIG_COMMISSIONER_ENABLE || OPENTHREAD_CONFIG_JOINER_ENABLE || OPENTHREAD_CONFIG_BLE_TCAT_ENABLE)
 #endif
 
-#if OPENTHREAD_CONFIG_DTLS_ENABLE
+#ifdef OPENTHREAD_CONFIG_DTLS_ENABLE
 #error "OPENTHREAD_CONFIG_DTLS_ENABLE is deprecated please use OPENTHREAD_CONFIG_SECURE_TRANSPORT_ENABLE instead"
 #endif